Lubricating oils that are suitable for use in modern engines must meet industry performance specifications. Today's engines are designed to run hotter and harder than in the past. However, an adverse affect of running hotter is that oxidation of the oils increases as the operating temperature of the oil increases. Oxidation of the oils can lead to a viscosity increase in the oil and the formation of high temperature deposits caused by agglomerated oxidation by-products baking onto lubricated surfaces. It is believed that these deposits can negatively affect engine performance by, for example, clogging fuel induction systems. Considerable research has been devoted to additives for controlling (preventing or reducing) deposit formation in internal combustion engines.
However, it is also known that some additives are very expensive. And, the use of additional amounts of an additive to a lubricant composition to reduce deposit formation can be quite costly to the manufacturer.
A major component of a lubricant composition can be the base oil, which is relatively inexpensive. Base oils are known and have been categorized under Groups I-V. The base oils are placed in a given Group based upon their % saturates, % sulfur content, and viscosity index. For example, all Group II base oils have greater than 90% saturates, less than 0.03% sulfur, and a viscosity index ranging from ≧80 to ≦120. However, not all Group II base oils are the same. For example, the proportions of aromatics, paraffinics, and naphthenics can vary substantially in the Group II base oils. It is known that the differences between base oils of a given Group can affect the properties of a lubricant composition comprising such as base oil, such as oxidative stability and deposit formation.
Hence, what is needed is a lubricant composition that is inexpensive and can provide reduced deposit formation.
Accordingly, there is a need for a lubricant composition that can reduce deposit formation as required by the new generation of engines. The present disclosure proposes a lubricant composition that can reduce deposit formation.